JPH08313634A - Personal dosimeter - Google Patents

Abstract

PURPOSE: To realize the structure in which radioactive ray flying from the forward direction is detected as it is without passing a pocket cloth and many radiation detectors can be disposed in the personal dosimeter mounted in a worker's pocket. CONSTITUTION: A clip block 26 is openably supported to a body 24. When the body 24 is inserted into a pocket 12, its pocket cloth 18 is sandwiched between the body 24 and the block 24. A plurality of radiation detectors 28 to 30 are disposed in the block 26 to detect radioactive rays without passing the cloth 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a personal dosimeter, and more particularly to a portable personal dosimeter used by being worn in a chest pocket or the like.

[0002]

2. Description of the Related Art Workers engaged in a radiation control area of a radiation handling facility such as a nuclear power plant are required to carry a personal dosimeter for personal exposure control. Conventionally, as such a personal dosimeter, for example, a personal dosimeter including a film batch or a semiconductor detector is known.

FIG. 4 shows an example of a conventional personal dosimeter incorporating a semiconductor detector. The personal dosimeter 10 is to be mounted in a chest pocket 12 of a worker's outer jacket,
In the illustrated example, a pen type is shown. The main body 14 of the dosimeter is inserted into the pocket 12, and only the upper portion of the main body 14 has the upper edge 18A of the pocket cloth 18 of the pocket 12.
It is exposed from above. A small clip 16 is arranged on the front surface of the main body, and a pocket cloth 18 is sandwiched between the clip 16 and the main body 14. In this conventional example, one semiconductor detector (hereinafter referred to as a detector) 20 is built in the upper portion of the main body 14, and specific radiation such as γ rays or β rays is detected. A display is provided on the back surface of the main body 14.

According to this structure, the detector 20 arranged in the upper portion of the main body 14 can detect not the radiation that has passed through the pocket cloth 18 but the radiation flying from the front as it is, so that the radiation is unnecessarily attenuated. Without
A highly accurate and reliable measurement of radiation can be realized. In particular, in the detection of β rays having a short range in the air, since the attenuation of the radiation energy by the pocket cloth 18 cannot be ignored, the radiation is measured so as not to be affected by the pocket cloth 18.

[0005]

However, in the above-mentioned conventional personal dosimeter, it is difficult to incorporate a plurality of detectors due to its structure. That is, the size of the exposed portion exposed from the pocket cloth 18 is limited, and the exposed portion in which the detector is built cannot be made too large. If the exposed portion is further extended upward, it will hinder the movement of the worker or the balance will be deteriorated, and the handleability of the personal dosimeter will be deteriorated. It is also possible to increase the width of the main body 14 and thereby widen the exposed portion in the lateral direction. With such a configuration, it may be possible to incorporate, for example, about two detectors. However, even in that case, there is a certain restriction on the lateral size of the pocket, and it is difficult to secure an area for arranging a large number of detectors such as four or five. Since each detector is accompanied by a circuit such as a preamplifier around it, it is necessary to consider the arrangement area of such peripheral circuits.

As described above, in the conventional personal dosimeter, it was difficult to incorporate a large number of detectors.

On the other hand, as is well known, radiation has a γ
There are various types of rays, β rays, neutron rays, etc. In order to measure and calculate the dose equivalent in a personal dosimeter, it is basically necessary to use a detector for each radiation. Further, in order to obtain the dose equivalent, it is necessary to match the response of the detector with a predetermined dose equivalent conversion function, and for that purpose, it is necessary to use a plurality of detectors having different filter characteristics. As described above, it is desired to arrange a large number of detectors in the personal dosimeter.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to secure a region in which a large number of detectors can be arranged in a personal dosimeter mounted in a pocket.

Another object of the present invention is to provide a personal dosimeter that can be reliably mounted in a pocket.

[0010]

In order to achieve the above object, the present invention is directed to a main body formed in a shape that can be inserted into a pocket, and rotatably supported at the upper end of the main body. A clip body that is a member that can be opened and closed, and in which, when the main body is inserted into a pocket, a pocket cloth is sandwiched in a gap formed between the main body and the pocket cloth, which appears outside the pocket and is used. And a radiation detection unit that is built in the clip body and that detects radiation coming from the front.

Further, the present invention is characterized in that the radiation detecting section is composed of a plurality of radiation detectors.

According to the present invention, the radiation detecting section is
Includes a radiation detector for detecting rays, a radiation detector for detecting β rays and a radiation detector for detecting neutrons, and a β ray incident window corresponding to the radiation detector for detecting β rays on the front surface of the clip body. It is characterized by being formed.

Further, the present invention is characterized in that the plurality of radiation detectors are arranged side by side in the vertical direction.

Further, the present invention is characterized in that a plurality of concavo-convex portions are formed on at least one of the front surface of the main body and the rear surface of the clip body so as to enhance the sandwiching of the pocket cloth.

Further, the present invention is characterized in that a biasing means for applying a biasing force to the clip body in a direction in which the clip body is closed is provided.

Further, the present invention is characterized in that a display for displaying the measurement result is formed on the back surface of the main body.

Further, according to the present invention, the first body is equipped with an electronic circuit for calculating a dose equivalent based on a detection result.
A second substrate on which a plurality of semiconductor detectors forming the detection unit and a plurality of preamplifiers provided for each of the semiconductor detectors are mounted; and The second substrate may be connected to each other by a flexible signal cable arranged around the upper end of the main body.

[0018]

According to the above construction, the main body is inserted into the chest pocket provided in the outer jacket of the operator with the clip body opened with respect to the main body. In this case, the pocket cloth is inserted into the gap between the main body and the clip body. Then, by closing the clip body, the pocket cloth is clamped by the main body and the clip body. This prevents the personal dosimeter from wobbling in the pocket or popping out by the movement of the worker, and the personal dosimeter can be reliably and stably mounted in the pocket.

In such a mounted state, only the upper part of the main body is exposed from the upper edge of the pocket cloth,
Rather, the exposure amount can be made smaller than in the conventional case. Then, since the clip body is located on the front side of the pocket cloth, the radiation can be detected without passing through the pocket cloth. That is, the entire clip body is exposed to the outside of the pocket, and therefore, the entire area of the clip body can be used as an arrangement area of the radiation detection unit.

The radiation detector provided on the clip body is
The radiation coming from the front is detected as it is without passing through the pocket cloth. Based on the detection result, the dose, dose rate, dose equivalent, etc. are obtained.

Here, the radiation detector is composed of a plurality of radiation detectors, for example, a radiation detector for γ-ray detection, β
It is composed of a radiation detector for detecting rays and a radiation detector for detecting neutrons. In this case, a β-ray incident window is formed on the front surface of the clip body so as to correspond to the β-ray detection radiation detector.

Generally, the shape of the pocket is long in the vertical direction, but if a plurality of radiation detectors are arranged in the vertical direction, the width of the main body and the clip body in the horizontal direction can be reduced, and the shape of the pocket can be reduced. A personal dosimeter that conforms to can be configured. Of course, the radiation detectors may be arranged side by side depending on the size of the pocket and the number of radiation detectors.

By forming a plurality of irregularities on at least one of the front surface of the main body and the back surface of the clip body, the personal dosimeter can be more reliably and stably mounted in the pocket. In particular, when the worker leans forward, the personal dosimeter is reliably prevented from falling due to its own weight.

In a preferred aspect of the present invention, biasing means is provided for applying a biasing force to the clip body in the direction in which it closes. This urging means strengthens the sandwiching of the pocket cloth. Further, on the back surface of the main body, a display device for displaying the measurement result is provided. The back of the main body is on the side of the human body, and if a display is provided on the back, the display can be protected from a physical collision or the like.

Further, in a preferred aspect of the present invention, the first board in the main body and the second board in the clip body are connected by a flexible signal cable to allow movement of the clip body. Here, the rotation angle of the clip body is at least an angle at which the pocket cloth can be inserted.

As described above, according to the present invention, since the radiation detecting portion is provided not on the main body but on the clip body appearing outside the pocket, the radiation detector can be provided with a sufficient space and the pocket cloth is not affected. Similar radiation measurements can be realized.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross section of a personal dosimeter according to the present invention, and FIG. 2 shows an external view of the personal dosimeter according to the present invention.

First, description will be made with reference to FIG. FIG. 2 (A)
Is a right side view of the personal dosimeter 22 of the present embodiment,
(B) is a front view of the personal dosimeter 22, and (C) is a rear view of the personal dosimeter 22.

The personal dosimeter 22 is roughly classified into a main body 24.
And a clip body 26. The main body 24 is to be inserted into a chest pocket of an operator and has an upper portion 24.
A clip body 26 is rotatably supported by A.
That is, the clip body 26 is opened and closed with respect to the main body 24 by using the upper portion 24A as a rotation axis. The open / closed state is shown in FIG.

The clip body 26 is exposed to the outside of the pocket when the main body 24 is inserted into the pocket, that is, the pocket cloth is placed in the gap 100 between the clip body 26 and the main body 24. Inserted and pinched by them.

As shown in FIG. 2, the upper portion 26A of the clip body 26 has a pair of support portions 24 formed on the main body 24.
It is rotatably held by B. That is, the rotation shaft is transversely provided between the support portions 24B.

As shown in FIG. 2B, the clip body 26 has five detectors 28, 30, 32, in this embodiment.
34, 36 are built in, and the preamplifiers 38, 40, 42, 4 corresponding to the respective detectors are provided in this clip body.
4, 46 are built in. In the present embodiment, the detectors 28 to 36 are semiconductor detectors, and the preamplifiers 38 to 46 amplify the detection signals of the semiconductor detectors respectively connected thereto. In this example,
The detectors 28, 30, 32 are semiconductor detectors for γ-ray detection, and they include metal filters having different filter characteristics. In order to match the response of the personal dosimeter 22 with the dose equivalent conversion function for calculating the dose equivalent, three such gamma ray detectors are arranged. The detector 34 is a semiconductor detector for β-ray detection, and a β-ray incident window is formed on the front surface thereof.
A metal mesh for protecting the inside of the β-ray incident window 48 and a light-shielding aluminized mylar are formed inside thereof. The detector 36 is a semiconductor detector for detecting neutrons, and a nuclear reaction layer is formed on the front surface of the semiconductor detector, where neutrons are converted into charged particles (for example, α rays), and the detector is used. It has been detected.

As described above, the personal dosimeter of this embodiment is
The dose equivalent is calculated by comprehensively measuring γ rays, β rays and neutron rays, and the dose equivalent is, for example, 1c.
m Dose equivalent is required. Of course, the type of dose equivalent may be switchable.

As shown in FIG. 2B, the personal dosimeter 22 of this embodiment is vertically long, and the length of the clip body 26 is set slightly shorter than that of the main body 24. Of course, the length of the clip body 26 can be appropriately determined according to the number of detectors.

In this embodiment, the detectors are arranged side by side in the vertical direction, and the detectors are arranged efficiently without increasing the width of the personal dosimeter 22. The personal dosimeter of this embodiment has a vertical length of, for example, 100 mm, a lateral width of, for example, 50 mm, and a thickness of, for example, 23 mm. The weight is, for example, about 100 g. The gap 100 described above
Is set to, for example, 2 mm when the clip body 26 is positioned parallel to the main body 24. Here, the lower end of the clip body 26 may be brought into contact with the main body 24.

As shown in FIG. 2 (C), a display unit 50 composed of a liquid crystal display is provided on the rear surface of the main body 24, and the dose equivalent which is the calculation result is displayed on this display unit 50. Since the display unit 50 is provided on the back side of the main body 24 in this manner, it is possible to protect the display unit 50 from an external impact when the personal dosimeter 22 is mounted in the pocket of the operator.

FIG. 1 shows a specific internal structure of the personal dosimeter 22 of this embodiment. As described above, the clip body 26 is rotatably supported by the rotating shaft 52 with respect to the main body 24. In order to allow this rotation, a cutout 54 is formed in the upper portion 26A of the clip body 26, and the upper end of the main body 24 is inserted into the cutout 54 when the clip body 26 is opened. Further, in the present embodiment, a spring 56 is provided in order to exert an urging force on the clip body 26 in the closing direction thereof. The spring 56 is wound around the rotary shaft 52, and one end thereof is clipped. 26, and the other end is engaged with a pin 58 formed on the main body 24. Of course, such biasing means is not limited to the illustrated spring 56, and other means may be used.

A circuit board-printed substrate 60 is disposed in the clip body 26, and the above-described detector 28 is mounted on the substrate 60.
~ 36 and preamplifiers 38 to 46 are mounted. Here, as described above, the β-ray incident window 48 is formed in front of the detector 34 for β-ray detection, and the β-ray incident window 48 is formed.
Is covered with a metal mesh and aluminized mylar for shading.

As shown in FIG. 1, the detector 34 for β-ray detection is arranged so as to project forward of the other detectors. This is because the incident angle of β rays is wide.
In front of the detectors 28, 30, 32, 36 is the clip body 2
6 front plate 26B, which is made of, for example, 1 mm of magnesium alloy or aluminum material.

The back plate 26C of the clip body 26 and the main body 24
As described above, the pocket cloth 18 of the pocket 12 is inserted and held in the gap 100 between the front plate 24B and the front plate 24B. The upper edge of the back plate 26C of the clip body 26 is bent in the horizontal direction toward the body side, and when the height of the pocket cloth 18, that is, the depth of the pocket 12 is deep in relation to the length of the body 24, the pocket is formed. The upper edge of the cloth 18 contacts the bent portion. On the other hand, when the depth of the pocket 12 is shallow, the bottom wall of the main body 24 contacts the bottom of the pocket 12. In any state, the pocket cloth 18 is sandwiched between the clip body 26 and the main body 24, and reliable and stable mounting of the personal dosimeter is achieved. In addition, the width of the main body 24 is set to be equal to or smaller than a size capable of being stored in the pocket 12.

In the main body 24, the circuit board-printed substrate 6 is provided.
2 is arranged, and a battery 64 is provided below the substrate 62.
And an electronic circuit 66 is arranged on the substrate 62. The electronic circuit 66 receives the output signal from each detector and calculates the dose, dose rate, dose equivalent, or the like as necessary. In this embodiment, basically the dose equivalent is calculated and displayed on the display 50. A flat cable 68 is connected between the substrate 60 and the substrate 62 as a flexible signal cable. Of course, this flat cable 68
Is flexible and has a certain amount of slack as described above, and therefore does not hinder the rotation of the clip body 26.

Since the battery 64 is arranged below, the center of gravity of the main body 24 can be lowered, and stable mounting of the personal dosimeter in the pocket 12 is achieved.

FIG. 3 shows a back plate 26C of the clip body 26.
Also, an embodiment in which a large number of jagged irregularities are formed on the front plate 24B of the main body 24 is shown. According to this structure, the sandwiching action of the pocket cloth 18 can be strengthened, and more reliable mounting can be achieved. It is desirable to form such a jagged shape on at least one of the main body 24 and the clip body 26, and it is preferable to form it on both of them as necessary. Of course, a rubber material having a large sliding friction force may be arranged without using such a structure.

In the embodiment described above, five detectors are arranged in series in the vertical direction, but of course the number of these detectors is not limited to that of this embodiment. When arranging more detectors, two detector rows may be formed. Alternatively, they may be arranged in a matrix.

[0046]

As described above, according to the present invention,
In a personal dosimeter mounted on a pocket, a large number of detectors can be arranged without radiation attenuation on the pocket fabric. In addition, it is possible to provide a personal dosimeter that can be reliably mounted in a pocket.

[Brief description of drawings]

FIG. 1 is a sectional view of a personal dosimeter according to the present invention.

FIG. 2 is a diagram showing an appearance of a personal dosimeter according to the present invention.

FIG. 3 is a diagram showing a configuration in which the holding force of the pocket cloth is enhanced.

FIG. 4 is a diagram showing an example of use of a conventional personal dosimeter.

[Explanation of symbols]

12 breast pockets, 22 personal dosimeters, 24 bodies, 2
6 clip body, 28, 30, 32, 34, 36 detector.

Claims (8)

[Claims] 1. A main body formed into a shape that can be inserted into a pocket, and a member that is rotatably supported by an upper end portion of the main body and that can be opened and closed with respect to the main body, wherein the main body is inserted into the pocket. In this case, the pocket cloth is sandwiched in the gap formed between the main body and the clip body that appears outside the pocket and is used, and the radiation that is built in the clip body and detects the radiation coming from the front side. A personal dosimeter including: a detection unit. 2. The personal dosimeter according to claim 1, wherein the radiation detection unit includes a plurality of radiation detectors. 3. The personal dosimeter according to claim 1, wherein the radiation detector includes a radiation detector for γ-ray detection, a radiation detector for β-ray detection, and a radiation detector for neutron detection, and the clip body. A personal dosimeter having a β-ray incident window formed on the front surface of the β-ray detector in correspondence with the β-ray detection radiation detector. 4. The personal dosimeter according to claim 2, wherein the plurality of radiation detectors are arranged side by side in the vertical direction. 5. The personal dosimeter according to claim 1, wherein at least one of the front surface of the main body and the back surface of the clip body is formed with a plurality of concave-convex portions for strengthening the sandwiching of the pocket cloth. Personal dosimeter. 6. The personal dosimeter according to claim 1, further comprising an urging means for applying an urging force to the clip body in a closing direction thereof. 7. The personal dosimeter according to claim 1, wherein a display for displaying the measurement result is formed on the back surface of the main body. 8. The personal dosimeter according to claim 1, wherein the main body includes a first substrate on which an electronic circuit that calculates a dose equivalent based on a detection result is mounted, and the clip body includes the detection unit. A second substrate on which a plurality of constituent semiconductor detectors and a plurality of preamplifiers provided for each of the semiconductor detectors are mounted, wherein the first substrate and the second substrate rotate within an upper end portion of the main body. A personal dosimeter, characterized in that they are connected to each other by a flexible signal cable arranged in a bundle.